📄 Archived: 2025-09-05 12:40:13 UTC
🔗 Source: https://www.lesswrong.com/posts/J8nvbu5AFqR5ysSDR/a-9-week-trip-on-retatrutide

# a 9-week trip on retatrutide

Warning: This is an experiment log, I’m not advising you to start taking GLP-1s. I wish that there were more logs about people's experiences on peptides, so here's mine in case others find it helpful.

I started Retatrutide in late May. I wasn’t overweight; I wanted more energy and focus. My BMI was 20.3-20.5 so I could lose about 5-7% of body weight without falling into the underweight category; I wore size 2-6 in women’s clothing; I deadlifted and squatted 3x5 (3 sets of 5 reps) about 0.85x my bodyweight, and I could overhead press about 0.3x of it. I went with Retatrutide because some people said that it helped them with focus etc.

I'm at my most productive when I’m slightly hungry, but not extremely hungry. This feature proves good for morning work, and bad for any sort of afternoon work after lunch (I get productive again right before dinner, which is annoying for dinner plans and going to sleep at a reasonable hour because I can't sleep right after eating). I had my (fasting) blood sugar tested two years ago and it was in the normal range. I also wore a CGM and played around with meal sizes and amounts of sugar, but energy levels and blood sugar did not seem to correlate much. I have tried to eat high protein with low carb or low fat and neither works; the only thing that really worked was to eat meals that had less than 300 calories. Which is not very conducive if I didn’t have the time the previous week to meal prep, and I had to consciously eat when I didn’t feel super hungry so I wouldn’t still feel quite hungry after 300 calories.

I had gained about 17 pounds over three years in college, and I lost 10 of those during graduate school (I did rapidly lose 10 lbs over 6 weeks right out of college because of budget constraints but I immediately gained back 5 lbs when the constraints were relaxed. I eventually lost the 5 lbs in the second year of grad school). I could lose weight, but I also wasn't really trying to lose weight, if that makes sense.

## Week 1-2

The typical dosing used in trials is 1 mg/week for the entirety, or 2 or 4 mg/week for 4 weeks and then staying on 4 mg/week for the rest of the trial, or titrating up to 8 or 12 mg/week. Most weight loss seemed to start around 4 mg.

I started at 0.5 mg/week, below any of the initial trial doses, but some forum users said that a lower dose would decrease the likelihood of side effects, and I was smaller than the typical Retatrutide user. I also had fairly bad side effects from some types of birth control, and I didn't want to risk having too much in my system and being in agony for a week.

During these two weeks, I would feel some semblance of hunger pangs, but they were extremely ignorable and in the background. My appetite mainly stayed the same, I think. I wore a CGM during the first week, and my blood sugar was far more stable, even when I'd eat something extremely sugary for lunch.

### Focus/Productivity

I don't think I was more productive per se, it was slightly easier for me to focus on things like writing (compared to coding which has a tighter feedback loop). I wrote a non-zero amount, but also not as much as I would have liked. But the lack of writing is also confounded with conference deadlines; I stayed up until 2 am one night to finish some experiments. My twitter usage went down slightly.

### Side effects

My sleep was definitely worse, I often would wake up a few hours before my normal wake time and fall back into some weird, troubled, dream-filled sleep. I felt tired in the mornings sometimes, but drinking electrolytes fixed it. I mostly stopped drinking caffeine in the mornings, and didn't get caffeine withdrawal (I have tried to quit previously and I would lead to headaches in the afternoon for the first few days).

My watch yelled at me for a lower HRV and higher resting stress, but that seems to a common side effect. My resting heart rate went up by 5 bpm.

In these two weeks, I didn’t really lose any weight, it just fluctuated within the normal range. The 7-day average at the end of the 2nd week was only 0.4% lower than my starting weight, which really rounds to zero (I actually gained 0.3 percentage points in the first week and then lost a bit more in the second week).

## Week 3-4

Then I went up to 1mg/week.

My reasoning was something like, “I’m feeling all the side effects (higher heart rate, worse sleep, low HRV) and only some of the benefits (a tiny bit of focus), maybe I should start being on the actual starting dose to see if there are any effects.”

### Focus/Productivity

Better focus kicked in after day 2 on 1 mg. I didn’t feel as tired before bed, but I’d often wake up tired until I drank electrolytes. My productivity went way up. I drafted an entire paper over the course of a week, including collecting and processing 75% of the data that I needed. This could be caused by stress because I really needed to get this thing done, but I have not been able to summon this type of productivity even during college (when I was arguably the most productive). I used to feel useless after 9 pm, and I haven't been able to wake up before 6 am to make use of the morning since third year of grad school, and now I can work between 9-11 pm. My twitter usage has gone down by about a third to about a half; I was writing a lot more than the past. Over the last year, I constantly had "oh I need to write" hanging over my head, but seldom would successfully put words on a page.

Hunger pangs were mostly gone; I could eat a meal a day and feel full, so I was roughly only eating two meals. I think there was a day where I only ate 200 calories and wondered why I was hungry in the evening. The hunger suppression was unironically great for productivity and I had a steady stream of energy throughout the day. I was constantly in the “a little bit hungry” state but almost never in the “ravenously hungry” level, my happy zone for productive work.

### Side effects

My watch continued to say that I didn’t sleep well, my HRV was low, and my exercise status was strained. My resting heart rate went up another 5 bpm (so 10 bpm higher than baseline). On the second week of 1 mg, I noticed that my heart rate went up higher much faster when climbing too. This means faster and easier warmups, but worse endurance when trying to finish a route. My lifts were about the same if not slightly heavier. I also sweated more.

Sometimes I’d eat at 8 or 9 pm, and this would cause acid reflux when I went to bed at 11 pm because Retatrutide slows down stomach emptying, and I’d still feel like there was a lot of food in my stomach. I could still eat normal-sized meals, but I didn't need as many normal-sized meals. I would sometimes eat something extremely sugary and not feel the sugar crash afterwards, but I don’t particularly crave sugary things anymore.

The rate of weight loss was the highest in these two weeks. My 7-day average at the end of Week 4 was slightly under 3% of original weight.

## Week 5

### Focus/Productivity

I worked fairly hard at the beginning of the week. I hit a major milestone in getting the paper done, but only had a week until the next deadline. I hit the second deadline on day 4.

On day 5, I crashed. I didn’t sleep more than usual, but my bandwidth significantly decreased. I didn’t feel like doing anything. This is likely caused by a combination of several things: I was on the last week of birth control where the hormones are significantly reduced (starting on day 2 of this week), I hit relevant deadlines about which I was extremely stressed for 2 weeks on day 5, and some other life stress right after too. I also suspect that I spent more time in the “ravenously hungry” zone because I felt hungry often but would ignore it (because I didn’t feel like doing anything); the hunger pangs would go away and I’d just be as tired as before. My twitter use went up at the end of the week, but it also goes up when I’m feeling dull in general.

### Side effects

I vomited on day 3 after exercising, because I had a protein bar too close to exercising (I don't recall vomiting before, but I also don't usually have a snack before climbing/lifting). I did deadlift 3x5 my body weight, up from 0.85x when I started this experiment.

My period also skipped, because of the rapid weight loss (this happened the summer I lost 10 lbs in 6 weeks naturally too).

I almost didn’t take the 6th dose and ended up delaying it by a day because I felt so tired, but I think I was physically more tired without Retatrutide because I was WAY more tired on day 8. This was partially intentional, partially I was too tired in the evening of the 7th day to think about injecting (last week, I used the same needle for drawing bacteriostatic water and injecting because I was spacey). By the evening of the 7th day, I felt quite tired and sluggish. On the morning of the 8th day, I felt extremely tired and almost missed work and I was like “okay this needs to stop.” Maybe Retatrutide just allows you to function better without enough food. I was eating roughly one meal and one snack.

I considered titrating down this week, but I wanted to see if the tiredness was entirely from external factors or due to Retatrutide, so I continued at the same dose.

I lost about another 1 percentage point this week, so 4.1% total.

## Week 6

I think most of the physical tiredness is from the type of birth-control I’m taking; the hormone-free week causes a crash in hormones, potentially leading to tiredness according to o3. After two days on a new pack, the physical tiredness went away.

I maybe was even slightly higher energy because I went climbing twice in the first half of the week and did a fun physical arcade evening with friends. But mentally I was still quite tired. It was rough getting me to do things; I went climbing multiple times because I wanted the silence in my head after physical exertion. I finally could squat 1x body weight for 3x5 too.

I lost about another percentage point of original weight, so about 5.3% total.

## Week 7

I decided to titrate up very slightly to 1.5 mg to see if it would deal with the mental tiredness. I shouldn’t have titrated up in hindsight.

### Focus/Productivity

After day 2, I had really strong lack of motivation to do anything. I’d stay in bed for hours after waking up and didn’t want to get out of bed; I didn’t want to go to sleep at night because that meant a new day. Not sure if this was due to uncertainty around work, dislike of my work location (we moved co-working spaces into a larger shared space), low-grade stress about paper edits, lack of protein, or some third thing.

### Side effects

I also really became *not* hungry at all when I physically felt hunger. I would not want to eat when my stomach was clearly empty and I should eat something. I typically ate things that I craved/wanted to eat, and earlier in the week I had issues with eating more than 200-300 calories in a meal. I ended up snacking on crackers a good bit this week.

I barely ate at all on 3rd day and that really messed up the 4th day because I felt very lightheaded in the morning but also nauseous when I had breakfast. I think I had some honey which helped with the lightheadedness and then had yogurt. But my stomach hurt for a bit and then subsided. At the end of the week, appetite suppression was still pretty strong and I felt like I couldn’t really eat normal-sized meals (equivalent of the previous week on day 2-3).

I’m now squarely in pre-college weight, lift 1x body weight, went up a climbing grade (this is likely just a function of time and climbing experience), probably lost some muscle but likely lost more fat because my proportions are still the same, just a bit smaller. I still wore the same clothes. Some did fit better, though.

I lost about 1.2 percentage points this week so I've lost 6.5% of original body weight so far.

## Week 8

I really should have titrated down to 1 mg this week.

### Focus/Productivity

Usually I feel a little tired but more focused after injecting, but I already was feeling somewhat uninterested in doing things, and it didn’t get better on day 2. I had to get paper edits done this week. This was pretty bad because I spent a good amount of time fighting myself to get work done.

I finally summoned up enough willpower to force myself to get this done on day 3 (I’m sorry Cate Hall, I know you disagree with this definition).

I hit the final deadline on day 5!

### Side effects

I vomited this week after going on a walk and eating a babka (which isn’t that much food?!) on day 3.

The most pressing thing done, I think I can conclude this experiment. I’m at a point where I shouldn’t be losing that much more weight. I often feel more low energy than usual on day 7, so I’ll try to titrate down instead of stopping cold turkey.

I've lost about 7.7% of original weight now.

## Week 9

I injected 1 mg this week; I didn’t realize how I mostly had gotten used to the lack of interest in doing things. I suddenly had motivation to do things again. I also spent less time on twitter this week compared to last week.

My appetite was still mostly gone, but I think I ate slightly more. I started eating breakfast (yogurt with chia seeds and hemp seeds), but I don’t know if this is because I regularly would skip dinner or the dosage was lower. But the hunger was comfortable—1.5 mg felt too strong where I would be hungry but not crave any food.

I still lost like 0.8 percentage points this week, so I've lost 8.5% of original weight so far.

I think I'll stop taking Retatrutide: my focus is slightly better, but my resting heart rate is close to 15 bpm higher than when I started, I would prefer to not sweat as much or have my heart rate spike as high during exercise. I would also like to get a good night of sleep again. I'm not sure if I'd have finished my dissertation this summer without Retatrutide, but I (hopefully) will be writing more code and fewer papers.

## Things that didn’t really fit into weekly reports:

This site has a nice graph of estimated concentrations of Retatrutide in my bloodstream throughout the experiment.

Here's a graph of how my BMI changed—I weighed in almost every morning, and my weight would end to tick up on the 5th or 6th day.

BMI trend throughout the experiment

I think I became slightly more forgetful/absent-minded because I misplaced items more frequently over the span of this experiment (thankfully I found most of them but some never turned up again). I typically don’t lose things; I think I've only lost one thing in the past year.

The amount I spent on food didn’t change because I already eat fairly frugally, if anything it went up as I ended up eating out more (mostly because I had more specific food cravings). If I was hungry enough, I’d eat anything but Retatrutide seemed to reduce that ability. I also did throw out more food because it went bad in the fridge.

Sarah Constantin said that she felt sleepy within 24 hours of the Ozempic shot; I actually felt quite alert and energetic right after an injection and moved my shots to the morning so I wouldn't have to consciously try to fall asleep.

Alcohol was strange. I had two standard drinks in one nights and felt hungover within three hours and still felt hungover in the morning. Before Retatrutide, I had never felt hungover in the morning (even after 3+ drinks), and I'd get a headache within an hour or so if I didn't drink enough water, and was fixable with water consumption. This time, I also didn't really feel a buzz when drinking alcohol, maybe something to do with the slower digestion on Retatrutide. I understand why alcoholics quit alcohol on GLP-1s, it's no longer fun anymore.

I exercised more over the course of this experiment than in the past, partially because I didn't want to lose muscle and partially because I got a smartwatch that would tell me nudge me to exercise (it's fun to see number go up in training load, for example).

My allergies towards dust weren't as bad as usual (I typically react to something in old houses and old furniture). I can't tell if this is due to weather changes or Retratrutide.

I suspect that the productivity benefits went away because I wasn't eating enough, and it takes a few weeks for your body to run out of fuel. I wish that I had tracked my food intake, because I was really tired on 1.5 mg and I definitely wasn't eating enough food.